Halton Rex Exposed VAV chilled beam is designed for high quality office requirements with high flexibility of the airflow adjustability. The Halton Rex Exposed VAV chilled operation will adapt to changes in the use of the space and office layout changes.

The chilled beam can be equipped with a duct cover to cover the connection duct and pipe installations (optional).

The front panel and side panels are made of pre-painted galvanised steel plate (white, RAL 9010). All visible parts can be painted with special colours (RAL xxxx).

The primary airflow rate is adjustable from minimum to maximum (0-100%) when static chamber pressure is kept constant. The chilled beam unit is equipped with a motorised Operation Mode Damper (OMD).

The induced room airflow rate is manually adjustable to three positions without influencing the primary air supply flow rate.

All pipes are manufactured from copper, connection pipes with a wall thickness of 0.9-1.0 mm. The fins of the heat exchanger are manufactured from aluminium. Heating is incorporated within the heat exchanger via two 10 mm pipes connected in series. All joints are factory pressure-tested.

The maximum operating pressure of the pipework is 1.0 MPa @ 70 °C. Each chilled beam is protected by removable plastic coating. Duct connection and pipe ends are sealed for transit. Each chilled beam is identifiable by a serial number printed on a label attached to the chilled beam.

Halton Rex Exposed VAV chilled beam is designed for high quality office requirements with high flexibility of the airflow adjustability. The Halton Rex Exposed VAV chilled operation will adapt to changes in the use of the space and office layout changes.

The primary supply air enters the plenum of the active chilled beam, from which it is diffused into the room through nozzles controlled by Operation Mode Damper (OMD). The supply air nozzle jets efficiently induce ambient room air through the heat exchanger, where it is either cooled or heated. The supply air jet is directed horizontally along the ceiling surface. The recommended minimum distance is 600 mm from the wall and 100 mm from the ceiling.

Fig.1. Function of the Halton Rex Exposed VAV beam

Velocity control in the occupied zone

Halton Velocity Control (HVC) is used for adjusting room air velocity conditions either when room layout is changed (e.g., in cases where the chilled beam is located near the partition wall) or when local, individual velocity conditions need to be altered. Halton velocity control adjustment has an impact on the induced room airflow through the heat exchanger, and therefore it either increases or decreases both the velocities in the occupied zone and the cooling/heating capacity of the chilled beam.

Halton Velocity Control involves manual velocity adjustment with three different positions (Fig.1. and 2.): 1 = Throttle, 2 = Normal, and 3 = Boost. The Halton velocity control system is divided into sections to enable the adjustment of conditions in different parts of the occupied zone. Depending on the length of the beam, optimal HVC damper module lengths between 500 and 1400 mm are used.

It is recommended to design the chilled beam in the normal position to allow both throttle and boost functions during the building s life cycle

Operation mode control

The supply airflow of the chilled beam nozzle jets is dependent on the nozzle type, nozzle row length and static chamber pressure.

The Operation Mode Damper (OMD, green in Fig. 4.) is used for adjusting and controlling the fresh airflow rate in a room space. The airflow rate is dependent on the opening position of the control damper. Operation mode of the room space is monitored with occupancy sensor.

Fig.4. OMD (green), Chamber 1 (blue) , Chamber 2 (red)

Fig.5. presents the function in different modes controlled by the OMD. In unoccupied mode (1.) the supply airflow rate is set to minimum value that can remove material emission. In occupied mode (2.) supply airflow rate is set to normal office mode. When more persons are coming to the space, based on CO2-sensor airflow is increased to boost mode (3.) to maintain the set target value of the indoor air quality.

1. Unoccupied mode 2. Occupied mode 3. Boost mode

Fig.5. Supply air modes of the Halton Rex Exposed VAV beam

It is recommended that chilled beams for demand based airflows should be connected to constant pressure ductwork zone.

Temperature controls

The cooling and heating capacities of the chilled beam are controlled by regulating the water flow rate according to the control signal of the room temperature controller.

In heating mode, it is recommended that the temperature difference between the jet outlet and room air would not be greater than 3 °C. The inlet water temperature of the heat exchanger should not be higher than 35 °C. Optimal heating performance requires an appropriate primary airflow rate. Thus, the air handling unit shall be in operation during heating periods to ensure proper heating performance.

The room controller manages the chilled beam operation by controlling chilled water and hot water control valves in 2- or 4-pipe applications.

The room controller provides a wide variety of connections for sensors and actuators and the possibility to connect a wall mounted panel with or without a display for local set points adjustment e.g. temperature, and a wireless remote control.

The Halton Rex Exposed VAV unit is suitable for exposed installation in the ceiling, typically lengthwise in the room. It is recommended to position the beam no closer than 600 mm from the wall and 100 mm from the ceiling. The chilled beam ceiling brackets can be fixed directly to the ceiling surface or suspended using threaded drop rods (8 mm). It is recommended that the brackets are positioned one quarter of a unit length (L/4) away from the end of the beam.

Install the main pipelines of the cooling and heating water loops above the level of the chilled beams to enable venting of the pipework.

Installation with brackets

Fig.1. Fixing of the beams done by pushing the beam to the ceiling brackets. Secure all fixing points so that they are properly locked to the fixing slots.

Cooling

The recommended cooling water mass flow rate is 0.02 … 0.10 kg/s, resulting in a temperature rise of 1 … 4 °C in the heat exchanger. To avoid condensation, the recommended inlet water temperature of the heat exchanger is 14 … 16 °C.

Heating

The recommended heating water mass flow rate is 0.01 … 0.04 kg/s, resulting in a temperature drop of 5 … 15 °C in the heat exchanger. The maximum recommended temperature of the inlet water for the heat exchanger is 35 … 45 °C.

Balancing and control of water flow rates

Balance the water flow rates of the Halton Rex Exposed VAV with adjustment valves installed on back end of the chilled beam. The cooling capacity and heating capacity of the chilled beam are controlled by regulating the water mass flow rate.

When setting the automatically balancing combination valve AB-QM, set the designed water flow rate in the valve body and verify the pressure difference (min.7.5 kPa) between the measurement nipples of the valve. The pressure difference over the valve must be 16 kPa, to ensure proper operation.

The water mass flow rate can be controlled by using an ON/OFF valve or a two- or three-way proportional valve.

Adjustment of supply airflow rate

Connect a manometer in the measurement tap and measure the static pressure in the Halton Rex Exposed VAV chilled beam. The measurement tab locations for OMD and chambers 1 and 2 are presented in Fig.1.

Remove the coil covers and front panel of the Halton Rex Exposed VAV. Clean the supply air plenum, duct and finned coils of the heat exchanger using a vacuum cleaner, taking care not to damage the finned coils. Clean the front panel and, if necessary, the side plates with a damp cloth.

The chilled beam can be equipped with a duct cover to cover the connection duct and pipe installations (optional).

The front panel and side panels are made of pre-painted galvanised steel plate (white, RAL 9010). All visible parts can be painted with special colours (RAL xxxx).

The primary airflow rate is adjustable from minimum to maximum (0-100%) when static chamber pressure is kept constant. The chilled beam unit is equipped with a motorised Operation Mode Damper (OMD).

The induced room airflow rate is manually adjustable to three positions without influencing the primary air supply flow rate.

All pipes are manufactured from copper, connection pipes with a wall thickness of 0.9-1.0 mm. The fins of the heat exchanger are manufactured from aluminium. Heating is incorporated within the heat exchanger via two 10 mm pipes connected in series. All joints are factory pressure-tested.

The maximum operating pressure of the pipework is 1.0 MPa @ 70 °C. Each chilled beam is protected by removable plastic coating. Duct connection and pipe ends are sealed for transit. Each chilled beam is identifiable by a serial number printed on a label attached to the chilled beam.

Halton is passionate about indoor environments. We offer business-enhancing products, systems, and services for comfortable, energy-efficient, and safe environments to customers who value people's wellbeing. Halton is involved from target-setting to facility use and focuses on creating positive indoor environment experiences for people.